Problem: If $a + b = -2$ and $x + y = -2$, what is $4x + 5a + 4y + 5b$ ?
$= 5a + 5b + 4x + 4y$ $= (5) \cdot (a + b) + (4) \cdot (x + y)$ $= (5) \cdot (-2) + (4) \cdot (-2)$ $= -10 - 8$ $= -18$